Power allocation for full duplex decode-and-forward cooperative relay system

The 5G communication system requires higher data rates and energy efficiency. Full-duplex (FD) communications can double the spectral efficiency in ideal conditions and in full-duplex relay systems the relay node works under full-duplex mode. There is a trade off between the signal and interference at the relay node because the transmitting signal of the node can be interference signal and desired signal in different links in the system, respectively. Proper power allocation can both suppress the residual self-interference for better performance and save power of the FD system. In this paper, we propose a power allocation approximation algorithm and a power allocation method based on genetic algorithm (GA) for a FD decode-and-forward (DF) cooperative relay system with residual self-interference. The end-to-end outage probability is chosen as the criterion of power allocation problem. Both the global power constraint and individual power constraint are investigated. The approximation algorithm shows great simplicity and has better performance with high SNR. For GA algorithm, numerical results show that the proposed power allocation scheme obviously improves the performance of the FD relay system with good convergence performance.